Baltic Amber

Fossil resins · also called Succinite, Bernstein, Yantar, Gintaras, Bursztyn, Prussian amber

Baltic amber is fossilised tree resin from the Eocene forests of northern Europe, recovered chiefly from the glauconitic sands known as the blue earth on the Sambian Peninsula. Mineralogically it is succinite, an amorphous organic material of hardness 2 to 2½, distinguished from other ambers by its succinic acid content.

What is Baltic amber?

Baltic amber is the fossilised resin of Eocene forests that stood in what is now Scandinavia and the southern Baltic, hardened over some forty million years and redeposited by rivers and the sea. Gemmologically it is an amorphous organic substance rather than a mineral, and its formal name is succinite.

Resin is not sap: sap carries sugars through a living tree, while resin is a defensive secretion poured over a wound or an insect boring. What turns it into amber is time — the volatile terpenes evaporate, the remaining molecules polymerise, and the material ends up insoluble and hard enough to polish. Resin that has not completed that process is copal, the material most often sold as amber. The parent tree is still argued over: nineteenth-century writers named a pine, Pinus succinifera, while later infrared work points towards the family of the Japanese umbrella pine, the Sciadopityaceae.

What gives Baltic amber its colour?

Colour in amber does not come from a chromophore in the mineralogical sense. Transparent material runs from pale yellow through honey to deep cognac, and the depth of that colour is largely a record of oxidation. Opacity is a separate variable, produced not by pigment but by microscopic gas bubbles suspended throughout the resin.

The two variables read independently. Bubble density decides whether a piece is glass-clear, faintly cloudy, or the dense opaque white called bone amber, butterscotch being the same structure at a warmer tone. Oxidation works inward from the surface, which is why old beads are darker at the rim than at the core. Green and red tones are almost always produced by heating.

How is Baltic amber identified?

Specific gravity between about 1.05 and 1.09 is the most useful figure, low enough that amber floats in saturated brine while glass and most plastics sink. The refractive index is near 1.54, the material is singly refractive, the lustre resinous, and the hardness only 2 to 2½.

The brine test disposes of the heavy imitations but not of copal, which is amber's real problem. Under crossed polarising filters amber shows strong anomalous double refraction from frozen internal strain, where a cast plastic shows nothing or a moulding swirl. Under longwave ultraviolet, natural Baltic amber gives a chalky bluish-white glow; pressed amber fluoresces unevenly, brightening at the boundaries between its fragments.

The distinguishing feature: succinic acid and the Baltic shoulder

Baltic amber is the only fossil resin containing succinic acid in quantity, generally cited at three to eight per cent, and that chemistry earns it the mineralogical name succinite. It also produces a diagnostic feature in infrared spectroscopy: a broad absorption shoulder near 1250 wavenumbers, universally called the Baltic shoulder.

The distinction matters commercially: Baltic amber trades above other fossil resins that look much like it. Infrared spectroscopy, used by Gem-A and the laboratories, is quick and non-destructive. The shoulder is present in succinite from the Sambian, Ukrainian and Bitterfeld occurrences and absent in Dominican, Mexican and Burmese ambers, in young copals, and in the other fossil resins found in the very same blue earth — gedanite, glessite, beckerite and stantienite all occur with Baltic amber, all look broadly like it, and none is succinite.

What are the insects in Baltic amber?

Baltic amber is the richest single source of Eocene terrestrial fossils known, and several thousand species have been described from it. Flies, midges, ants, spiders, beetles and mites dominate; plant fragments, oak hairs and, very rarely, a lizard or a feather occur. Inclusions are preserved in three dimensions rather than flattened.

Resin captured what walked, flew or fell onto a trunk, which biases the record towards small arthropods and against anything large enough to pull free. Preservation is a mould rather than a mummy: surface detail survives while the tissues have degraded, which is why claims of recoverable ancient DNA have failed. Genuine inclusions are usually small, often incomplete, and frequently veiled by a whitish film of emulsified resin; a large, whole insect posed centrally in flawless yellow is the classic fake.

Is Baltic amber treated?

A large proportion of the Baltic amber on the market is treated, and the processes are so long established they often go unmentioned at the counter. Clarification of cloudy material by heating in oil, autoclave treatment under pressure to clarify or darken, and pressing of fragments into ambroid are the three to ask about.

Clarification drives the gas bubbles out of clouded amber. Traditionally that was done in rapeseed or linseed oil; modern practice uses an autoclave with an inert gas, which also allows darkening to cognac and red tones and the production of green amber. The same processes cause the disc-shaped fractures called sun spangles, sometimes marketed as natural. They are not: they are made deliberately by rapid cooling. Pressed amber, or ambroid, is waste fragments forced together under heat and pressure, showing flow structure, elongated bubbles and reddish seams under magnification.

Where does Baltic amber come from?

The Sambian Peninsula in the Kaliningrad region of Russia holds by far the largest known concentration, worked in an open pit at Yantarny where the amber-bearing horizon is a glauconitic sand called the blue earth. Poland, Lithuania, Latvia, Denmark, Ukraine and Bitterfeld in Germany supply the rest.

The blue earth is a marine sediment, not a forest floor: the resin was eroded out of the ground where it formed and concentrated in green-grey sands offshore. That is why Baltic amber occurs as waterworn nodules rather than as drips still attached to wood, and why storms still throw fresh material onto the beaches of Poland, Lithuania and Latvia. Lithuania's Juodkrantė deposit in the Curonian Lagoon was dredged out in the nineteenth century. Ukrainian amber from Klesiv and the Rivne region is Eocene succinite of the same character, and Bitterfeld amber from the Saxon lignite workings is chemically succinite, though its relationship to the Sambian deposit is still discussed.

Where the name comes from

Three unrelated names attached themselves to the same substance. The Greek elektron gave us electricity, because rubbed amber attracts light objects. The Latin succinum, from succus, sap, gave succinite and succinic acid. English amber comes through Old French from the Arabic anbar, which properly meant ambergris, a quite different material.

The German Bernstein records the plainest observation of all: it burns. Thales of Miletus is credited with noting amber's electrostatic behaviour in the sixth century BC, and electricity descends from that observation by way of William Gilbert's Latin coinage. It travelled south along the Amber Road long before any of those names were written. Its best-known object is the Amber Room at the Catherine Palace outside St Petersburg, looted in 1941 and never recovered.

What sizes are available?

Amber is available in sizes no mineral gem can match. Beads, cabochons and carvings of many centimetres are ordinary, and the largest recorded lumps run to several kilograms. What is scarce is not size but soundness: large pieces free of crazing, internal fractures and cloudy patches.

The price curve therefore behaves unlike that of a faceted mineral gem. There is no sharp step at one carat or at five, because rough of that weight is unremarkable; the step comes where a piece is big enough and clean enough to yield a substantial carving or a bead necklace matched for colour throughout, and matching is the real constraint, since colour varies from nodule to nodule and oxidation keeps moving it.

How much is Baltic amber worth?

Amber is priced on transparency, colour, size and, above all, on whether it is natural, treated, pressed or an inclusion specimen. Untreated transparent material of even colour, and dense white butterscotch, command the most in jewellery. A well-preserved, identifiable insect can be worth many times the amber around it.

The order of those factors shifts with the market. In the Middle East and East Asia, opaque white and butterscotch amber has long been valued above transparent cognac; Europe has generally paid more for clarity. Across both, treatment status is the largest single divider, and pressed amber sits far below natural. The inclusion market is separate again, driven by the rarity and completeness of the organism rather than by any of the qualities that price the coloured stones on our gems pages.

Is Baltic amber durable enough to wear?

Amber is soft, at 2 to 2½ on the Mohs scale, among the least durable materials in jewellery use. It scratches against almost everything, including household dust, it is brittle, and it is attacked by alcohol, acetone, perfume and hairspray. It also darkens and eventually crazes on long exposure to air and light.

None of this has stopped amber being worn for four thousand years, but it dictates how. Beads, pendants, brooches and earrings are appropriate; a ring is a short-lived proposition. Never clean amber ultrasonically or with steam, and keep a torch away from a mounted piece: it softens well below the temperature at which a jeweller works metal. Warm water, mild soap and a soft cloth is the whole routine.

How to buy Baltic amber without being caught out

Establish four things in writing before paying: that the material is amber and not copal or plastic, that it is Baltic and not another fossil resin, that it is natural rather than pressed, and what heat or oil treatment it has had. A seller unable to answer the last two plainly is the problem.

Take the piece in your hand first: amber is warm to the touch and conspicuously light for its size, where glass is cold and heavy. Look for mould seams along a bead's girdle and for perfectly spherical bubbles, both signs of casting. Regular, evenly spaced sun spangles mean heat treatment whatever the label says; reddish seams and elongated bubbles mean pressed amber. If inclusions are the point, be more sceptical the more attractive the insect is, and ask the question our specimens shelves ask — who identified it, and on what evidence. For anything of consequence an infrared spectrum settles the Baltic question, and we arrange independent testing through our services.

Looking to buy baltic amber? See the collection, the rough, or send us a brief.